• Title/Summary/Keyword: 추세 분석

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Computing the Dosage and Analysing the Effect of Optimal Rechlorination for Adequate Residual Chlorine in Water Distribution System (배.급수관망의 잔류염소 확보를 위한 적정 재염소 주입량 산정 및 효과분석)

  • Kim, Do-Hwan;Lee, Doo-Jin;Kim, Kyoung-Pil;Bae, Chul-Ho;Joo, Hye-Eun
    • Journal of Korean Society of Environmental Engineers
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    • v.32 no.10
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    • pp.916-927
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    • 2010
  • In general water treatment process, the disinfection process by chlorine is used to prevent water borne disease and microbial regrowth in water distribution system. Because chlorines were reacted with organic matter, carcinogens such as disinfection by-products (DBPs) were produced in drinking water. Therefore, a suitable injection of chlorine is need to decrease DBPs. Rechlorination in water pipelines or reservoirs are recently increased to secure the residual chlorine in the end of water pipelines. EPANET 2.0 developed by the U.S. Environmental Protection Agency (EPA) is used to compute the optimal chlorine injection in water treatment plant and to predict the dosage of rechlorination into water distribution system. The bulk decay constant ($k_{bulk}$) was drawn by bottle test and the wall decay constant ($k_{wall}$) was derived from using systermatic analysis method for water quality modeling in target region. In order to predict water quality based on hydraulic analysis model, residual chlorine concentration was forecasted in water distribution system. The formation of DBPs such as trihalomethanes (THMs) was verified with chlorine dosage in lab-scale test. The bulk decay constant ($k_{bulk}$) was rapidly decreased with increasing temperature in the early time. In the case of 25 degrees celsius, the bulk decay constant ($k_{bulk}$) decreased over half after 25 hours later. In this study, there were able to calculate about optimal rechlorine dosage and select on profitable sites in the network map.

The Risk Assessment of the Fire Occurrence According to Urban Facilities in Jinju-si (진주시 도시시설물별 화재발생 위험도 평가)

  • Bae, Gyu Han;Won, Tae Hong;Yoo, Hwan Hee
    • Journal of Korean Society for Geospatial Information Science
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    • v.24 no.1
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    • pp.43-50
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    • 2016
  • Urbanization in Korea has increased significantly and subsequently, various facilities have been concentrated in urban areas at high speed in accordance with a growing urban population. Accordingly, damages have occurred due to a variety of disasters. In particular, fire damage among the social disasters caused the most severe damage in urban areas along with traffic accidents. 44,432 cases of fire occurred in 2015 in Korea. Due to these accidents, 253 were killed and property damage of 4,50 billion won was generated. However, despite the efforts to reduce a variety of damage, fire danger still remains high. In this regard, this study collected fire data, generated from 2007 to 2014 through the Jinju Fire Department and the National Fire Data System(NFDS) and calculated fire risk by analyzing the clustering of fire cases and facilities in Jinju-si based on the current DB of facilities, offered by the Ministry of Government Administration and Home Affairs. As a result, the risk ratings of fire occurrence were classified as four stages under the standards of the US Society of Fire Protection Engineers(SEPE). Business facilities, entertainment facilities, and automobile facilities were classified as the highest A grade, detached houses, Apartment houses, education facilities, sales facilities, accommodation, set of facilities, medical facilities, industrial facilities, and life service facilities were classified as U grade, and other facilities were classified as EU grade. Finally, hazardous production facilities were classified as BEU grade, the lowest grade. In addition, in the case of setting the standard with loss of life, the highest risk facility was the hazardous production facilities, while in the case of setting the standard with property damage, a set of facilities and industrial facilities showed the highest risk. In this regard, this study is expected to be effectively utilized to establish the fire reduction measures against facilities, distributed in urban space by calculating risk grades regarding the generation frequency, casualties, and property damage, through the classification of fire, occurred in the city, according to the facilities.

An Analysis of Terrorism against Korea to Overseas and its Implications - Focusing on the companies advancing to overseas - (한국을 대상으로 한 국제테러리즘의 분석과 시사점 - 해외진출기업을 중심으로 -)

  • Chang, Suk-Heon;Lee, Dae-Sung
    • Korean Security Journal
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    • no.28
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    • pp.153-179
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    • 2011
  • Korea has been a victim of State supporting terrorism by North Korea even before international society realize the terrorism threats because of 9.11 in US. However, state supporting terrorism against South Korea by North Korea went along with East/West Cold War System by US and the Soviet Union. It is because socialism that Kim Il-sung who established a separate government in North Korea with the political, economic, social and military support of the Soviet Union selected as his political ideology justifies terrorism as the tool to complete the proletariat revolution. North Korea's state supporting terrorism is being operated systematically and efficiently by military of North Korea. It gives big worries to international society not only by performing terrorism against Korea but also by dispatching terrorists and exporting terrorism strategies to the third world countries. In this situation, terrorism against Korea has met a new transition point at 9${\cdot}$11 in US. As South Korea is confronting North Korea and the war has not ended but suspended, the alliance between US and Korea is more important than anything else. Because of this Korea decided to support the anti-terrorism wars against Afghanistan and Iraq of US and other western countries and send military force there. The preface of the anti-terrorism war has begun as such. On October 7, 2001, US and UK started to attack Afghanistan and Taleban government in Afghanistan was dethroned on December 7, 2001. US and western countries started a war against Iraq on March 20, 2003. On April 9, 2003 Baghdad, the capital of Iraq fell, and Saddam Hussein al-Majid al-Awja government was expelled. During the process, the terrorism threat against South Korea has expanded to Arab terrorists and terrorism organizations as well as North Korea. Consequently, although Korean government, scholars and working level public servants made discussions and tried to seek countermeasures, the damages are extending. Accordingly, terrorism against Korean companies in overseas after 9${\cdot}$11 were analyzed focusing on Nation, Region, Victimology, and Weapons used for the attacks. Especially, the trend of terrorism against the Korean companies in overseas was discussed by classifying them chronologically such as initiation and termination of anti-terrorism wars against Afghanistan and Iraq, and from the execution of Iraqi President, Saddam Hussein al-Majid al-Awja to December 2010. Through this, possible terrorism incidents after the execution of Osama bin Laden, the leader of Al-Qaeda, on May 2, 2011 were projected and proposals were made for the countermeasures.

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The Surgical Case Analysis of Congenital Heart Disease -A review of 1,060 Cases (선천성 심장병의 외과적 고찰)

  • Jo, Sam-Hyeon;O, Bong-Seok;Lee, Dong-Jun
    • Journal of Chest Surgery
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    • v.29 no.12
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    • pp.1316-1322
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    • 1996
  • From May 1977 to December 1994, 1.060 cases of open heart surge y for congenital heart disease were performed under cardiopulmonary bypass in Chonnam University Hospital They were divided into two groups; group A(677 cases, from May 1977 lo December 1989), group B(38B cases, from January 1990 to December 1994), to be compared and analized. Of the 1, 060 cases, there were 889 acyanotic (83.9%) and 171 cyanotic(16.1%). The operative mortality was 7.8% in group A and 5.7% in group B (total : 6.6%). The operative mortality for group A was 25% in cyanotic disease and 3.7% in acyanotic disease, respectively in group B, it was 23.8%, 3.2%. There were 19 patients (3.8%) and 78 patients(20.4%) with body weight under 10kg in group A and group B respectively. The operative mortality for these patients were 31.6% in A group and 16.1% in B group. In result, increasing trend in congenital heart disease in patients under 10 kg of body weight has been noted, whereas mortality has decreased. The operative mortality of tetralogy of Fallot has decreased in group B t an group A. These results suggest that the operative result have improved in recent years.

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Association of Liver Dysfunction with Self-Medication History in Korean Healthy Male Adults (건강한 한국 성인남성의 자가약물복용력에 따른 간기능 장애 발생여부 조사)

  • Bae, Jong-Myon;Park, Byung-Joo;Lee, Moo-Song;Kim, Dong-Hyun;Shin, Myung-Hee;Ahn, Yoon-Ok
    • Journal of Preventive Medicine and Public Health
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    • v.29 no.4 s.55
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    • pp.801-814
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    • 1996
  • Background: Korean people could abuse healthy foods as well as medications, which might cause serious side effects. The aim of this study was elucidating liver dysfunction due to the self-medications of hepatotonics, healthy foods and herb medications by nested case-control study. Methods: Study subjects were drawn from male members of Seoul Cohort Study who were recruited by self-administered structured questionnaire survey through mailing to the healthy men between the age of 40 and 59 years through the program of biennial health check-up offered by Korea Medical Insurance Corporation(KMIC). The liver dysfunction was defined as the level of serum AST and ALT above 40 IU/L and increased in more than one hunderd per-cent during the 2 year follow-up period. To estimate the odds ratio between self-medication and liver dysfunction after controlling for potential confounders, logistic regression was performed. Results: During the follow-up period, 30 members were identified to fit into case criteria and 2,625 members were selected as control. In logistic regression analyses, history of healthy foods intake, age under 45 years, obesity, and habit of regular exercise were significantly associated with liver dysfunction. The following factors exhibited no statistical significance: intake of hepatotonics, of herb medicine; history of disease in family, of operation, and of radiologic examination; smoking habits and drinking amounts. Conclusion: The significant association between the intake of healthy foods and the liver dysfunction illustrates that chronically optional overuse of healthy foods might bring to hazards to health. As the increasing trend of the size of purchasing healthy foods in Korea, pharmacoepidemiologic studies evaluating the safety and efficacy of the widely used healthy foods should be performed in the near future.

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Comparison of Anti-oxidative Activity in a Single Serving Size of the Commercial Coffees and Teas

  • Kim, Tae-Hun;Lee, Seulgi;Seo, Jin Woo;Bing, Sun Hye;Kim, Jong Im;Kwon, Eui-Ra;Jo, Gune-Hee;Lee, Jae-Myean;Choi, Joon Sig
    • Journal of Food Hygiene and Safety
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    • v.32 no.6
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    • pp.460-469
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    • 2017
  • The aim of this work was to study the comparison of anti-oxidative activity in a single serving size of commercial coffees and teas. Commercial regular coffees and teas, including, brand regular coffees ($BC_A$, $BC_B$, $BC_C$, $BC_D$, and $BC_E$), green tea ($GT_A$, $GT_B$, $GT_C$, and $GT_D$), black tea ($BT_A$, $BT_B$, and $BT_C$), pu-erh tea ($PT_A$, $PT_B$, and $PT_C$), chamomile tea ($CT_A$, $CT_B$, and $CT_C$), peppermint tea ($P_A$, $P_B$, and $P_C$), polygonatum odoratum tea ($POT_A$, $POT_B$, and $POT_C$), and jujube tea ($JT_A$, $JT_B$, and $JT_C$) were assayed for the levels of ascorbic acid, caffeine, total content of polyphenols and flavonoids, and ability to scavenge free radicals, using two in vitro antioxidant assays. The scavenging abilities of $BC_A$ and $BC_C$ were $664.91{\pm}48.87mg$ ascorbic acid equivalent/serving size and $624.36{\pm}16.18mg$ ascorbic acid equivalent/serving size, respectively. The four beverage samples ($BC_A$, $BC_C$, $GT_D$, and $BT_A$) significantly reduced the production of reactive oxygen species (ROS) and intracellular oxidative stress induced by $H_2O_2$. These results suggest that the beverages possess significant radical scavenging ability, which may be due to the presence of antioxidants. Furthermore, the significant reducing level of ROS evidences the potential antioxidant effects of these beverages in human cells.

A Survey on the Satisfaction for School Lunch Program of Middle- and High School Students in Metropolitan Area (수도권 거주 중.고등학생의 점심식사 만족도 조사)

  • Kim Yong-Sun;Song Tae-Hee;Woo In-Ae;Choi Hee-Sook
    • The Korean Journal of Food And Nutrition
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    • v.17 no.4
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    • pp.429-435
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    • 2004
  • As the school lunch program is expanding to middle and high schools in Korea, a survey has been conducted to provide informations of the types and menus which are most favored on 190 middle and high school students in Metropolitan area. The sources/menus of foods relating to their lunches were proportionally ranked as: school food services (54.2%): individual lunch-box from home(37.4%); take-out lunch box(3.7%): school cafeterias(1.6%): and commercial restaurant, undefined, and skip a meal(1.1%). For the present practices for lunch, 52.1 and 47.9% of the students responded satisfaction on its sources and menus, respectively. A meal valued less than 2,000 won was paid by 54.9% of the respondents. In the meantime, 33.7 and 55.4% of the students were unsatisfied with lunch box from home and school cafeteria of the present lunch practices, respectively. The reasons against their satisfactions were enumerated as their preferences for take-out lunch box(22.2%), school cafeteria(21.0%), outside restaurant(17.3%), individual lunch-box from home(16.1%), school cafeterias(8.6%), and undefined (14.8%). For the individual lunch-box from home, two major obstacles, i.e., it is neither warm to eat, nor diverse/properly-sized in side dishes, were reasons for dissatisfaction of the students. The school lunch programs were blamed for its poor taste and lacks of variety and volume of the side dish which is mostly composed of kimchi, seasoned vegetables, and bulgogi. The most popular side dishes were pork- or fish cutlets, hams, and sausages while food with carrots, garlics or red peppers, vegetables like pumpkins, lotus roots, and seasoned vegetables were mostly disliked. It was concluded that the school lunch programs for middle- and high school students could be settled down by preparing with well-nourished food items that suits students' taste best and be served at right temperature.

Precise, Real-time Measurement of the Fresh Weight of Lettuce with Growth Stage in a Plant Factory using a Nutrient Film Technique (NFT 수경재배 방식의 식물공장에서 생육단계별 실시간 작물 생체중 정밀 측정 방법)

  • Kim, Ji-Soo;Kang, Woo Hyun;Ahn, Tae In;Shin, Jong Hwa;Son, Jung Eek
    • Horticultural Science & Technology
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    • v.34 no.1
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    • pp.77-83
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    • 2016
  • The measurement of total fresh weight of plants provides an essential indicator of crop growth for monitoring production. To measure fresh weight without damaging the vegetation, image-based methods have been developed, but they have limitations. In addition, the total plant fresh weight is difficult to measure directly in hydroponic cultivation systems because of the amount of nutrient solution. This study aimed to develop a real-time, precise method to measure the total fresh weight of Romaine lettuce (Lactuca sativa L. cv. Asia Heuk Romaine) with growth stage in a plant factory using a nutrient film technique. The total weight of the channel, amount of residual nutrient solution in the channel, and fresh shoot and root weights of the plants were measured every 7 days after transplanting. The initial weight of the channel during nutrient solution supply (Wi) and its weight change per second just after the nutrient solution supply stopped were also measured. When no more draining occurred, the final weight of the channel (Ws) and the amount of residual nutrient solution in the channel were measured. The time constant (${\tau}$) was calculated by considering the transient values of Wi and Ws. The relationship of Wi, Ws, ${\tau}$, and fresh weight was quantitatively analyzed. After the nutrient solution supply stopped, the change in the channel weight exponentially decreased. The nutrient solution in the channel slowly drained as the root weight in the channel increased. Large differences were observed between the actual fresh weight of the plant and the predicted value because the channel included residual nutrient solution. These differences were difficult to predict with growth stage but a model with the time constant showed the highest accuracy. The real-time fresh weight could be calculated from Wi, Ws, and ${\tau}$ with growth stage.

THE INFLUENCE OF pH AND LACTIC ACID CONCENTRATION ON THE FORMATION OF ARTIFICIAL ROOT CARIES IN ACID BUFFER SOLUTION (산 완충용액의 pH 및 유산의 농도가 인공치근우식의 형성에 미치는 영향)

  • Oh, Hyun-Suk;Roh, Byoung-Duck;Lee, Chan-Young
    • Restorative Dentistry and Endodontics
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    • v.32 no.1
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    • pp.47-60
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    • 2007
  • The purpose of this study is to compare and to evaluate the effect of pH and lactic acid concentration on the progression of artificial root caries lesion using polarizing microscope, and to evaluate the morphological changes of hydroxyapatite crystals of the demineralized area and to investigate the process of demineralization using scanning electron microscope. Artificial root caries lesion was created by dividing specimens into 3 pH groups (pH 4.3, 5.0, 5.5), and each pH group was divided into 3 lactic acid concentration groups (25 mM, 50 mM, 100 mM). Each group was immersed in acid buffer solution for 5 days and examined. The results were as follows : 1. Under polarized microscope, the depth of lesion was more effected by the lactic acid concentration rather than the pH. 2. Under scanning electron microscope, dissolution of hydroxyapatite crystals were increased as the lactic acid concentration increased and the pH decreased. 3. Demineralized hydroxyapatite crystals showed peripheral dissolution and decreased size and number within cluster of hydroxyapatite crystals and widening of intercluster and intercrystal spaces as the pH decreased and the lactic acid concentration increased. 4. Under scanning electron microscope evaluation of the surface zone, clusters of hydroxyapatite crystals were dissolved, and dissolution and reattachment of crystals on the surface of collagen fibrils were observed as the lactic acid concentration increased. 5. Under scanning electron microscope, demineralizatlon of dentin occurred not only independently but also with remineralization simultaneously. In conclusion, the study showed that pH and lactic acid concentration influenced the rate of progression of the lesion in artificial root caries. Demineralization process was progressed from the surface of the cluster of hydroxyapatite crystals and the morphology of hydroxyapatite crystals changed from round or elliptical shape into irregular shape as time elapsed.

The Changes of Smart Device Usage Status in Early Childhood: Comparison of 2015-2016 and 2017 Studies (유아 스마트 기기 사용 현황의 변화: 2015-2016년과 2017년의 연구 결과 비교)

  • So, Hyejin;Lim, Sungmin;Cho, Sang Yeun;Koh, Min Suk;Moon, Jin-Hwa
    • Journal of the Korean Child Neurology Society
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    • v.26 no.4
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    • pp.251-262
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    • 2018
  • Purpose: This study aimed to identify changes in smart device usage trends of young children using two studies conducted in 2015-2016 and 2017 respectively. Methods: We compared the data of the previous study of 130 children (Group A) and the new study of 162 children (Group B). The children and parents were recruited from kindergartens in Seoul and Guri/Namyangju cities. We used the "Parental questionnaire for smart device usage status." Results: There were some changes in the smart device usage in young children and parental perception. In the 2017 study, smart device usage time increased during weekends (P<0.05) and the usage with siblings decreased (P<0.05). In 2017, the smart device was mostly used when children had to be quiet without disturbing others (36.8%). No significant difference existed in the main purpose of use: watching video clips (79.3% vs 76.6%). Overall control of the usage was still largely exercised by mothers; however, when using applications, mothers still only helped the children on request (51.8% vs 49.7%). Regarding the effect of smart device on children, responses of "not knowing" decreased and "will be negative" and "will be positive" increased (P<0.05). Additionally, most mothers thought that "Although the smart device is currently unnecessary, it will be needed in future" in 2017 (46.3%). Conclusion: Limiting the smart device usage time during the weekends and increasing parental involvements are recommended. Guidelines for smart devices usage in young children are also necessary considering the changes in parental attitudes in recognizing the smart device usage as unavoidable.